In contemporary battery powered electric motor system applications, such as an electric vehicle, the vehicle's battery must be periodically recharged after being depleted during use. Often the vehicle's batteries are charged using a charger mounted on the vehicle. Typically, an AC current source--such as a source from a common wall outlet is transformed by the battery charger to replenish the depleted battery.
Because of various conditions characteristic of depleted batteries, the battery charger must be able to alternatively boost, or increase, a source voltage from the wall outlet as well as buck, or decrease, the source voltage from the wall outlet depending on a state of the battery. In one case, if the battery has been significantly depleted, then the source voltage must be decreased to be more proximate a terminal voltage of the depleted battery. If it isn't then it is difficult to effectively control the replenishment of the depleted battery. In another case, if the battery's terminal voltage is significantly higher than the source voltage, then the source voltage must be increased or boosted to be higher than the battery's terminal voltage so that current can flow from the battery charger to the battery.
If, as stated above, the battery charger is mounted on the vehicle a charger of this functional complexity can add not-insignificant weight to the vehicle. This is particularly concerning in the case of an electrical vehicle because efficiency is extremely important.
What is needed is an improved vehicular based motor control with integral battery charger that is lightweight and reliable.